| 1 | English | monotonous | Having an unvarying tone or pitch; Tedious,... |
| 2 | English | monotone | Having a single unvaried pitch; Being, or having... |
| 3 | Latin | monotonus | unvarying in tone |
| 4 | Greek | μονότονος | monotonous, flat; dull, boring |
| 5 | Greek | τόνος | ΄ tonos; note, pitch, tone; shade |
| 6 | French | tonne | tonne, metric ton; ton; first-person singular... |
| 7 | Latin | tunna | tun, box |
| 8 | Proto-Celtic | tondā | skin; surface, skin |
| 9 | Proto-Indo-European | tend- | to stretch, to extend; to split, cut off |
| 10 | Proto-Indo-European | temh₂- | to stretch, string; to cut |